Settlement, environment, and climate change in SW Anatolia: Dynamics of regional variation and the end of Antiquity

This paper develops a regional dataset of change at 381 settlements for Lycia-Pamphylia in southwest Anatolia (Turkey) from volume 8 of the Tabula Imperii Byzantini–a compilation of historical toponyms and archaeological evidence. This region is rich in archaeological remains and high-quality paleo-climatic and -environmental archives. Our archaeological synthesis enables direct comparison of these datasets to discuss current hypotheses of climate impacts on historical societies. A Roman Climatic Optimum, characterized by warmer and wetter conditions, facilitating Roman expansion in the 1st-2nd centuries CE cannot be supported here, as Early Byzantine settlement did not benefit from enhanced precipitation in the 4th-6th centuries CE as often supposed. However, widespread settlement decline in a period with challenging archaeological chronologies (c. 550–650 CE) was likely caused by a “perfect storm” of environmental, climatic, seismic, pathogenic and socio-economic factors, though a shift to drier conditions from c. 460 CE appears to have preceded other factors by at least a century.


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Introduction
Past climatic and environmental conditions are often considered influential for sociocultural change in Anatolia and the broad Eastern Mediterranean-Middle East region (e.g., [1][2][3]. Large-scale analyses are often necessitated, but also hindered, by low availability of high-quality comparable interdisciplinary datasets proximate to one-another (e.g., the Negev desert [4,5]. This presents difficulties in analysis as both climatic and socio-economic conditions display high spatial and temporal variability [6][7][8]. Here, we develop a regional settlement change dataset for Lycia and Pamphylia in SW Turkey (Figure 1), adapted from volume 8 of the Tabula Imperii Byzantini (TIB 8: [9]) -a compilation of historical toponyms and associated archaeological research [10]. The region is rich in the archaeological remains of cities, harbours, and rural settlements, in addition to high-quality palaeo-climatic andenvironmental datasets. Previously, the archaeological evidence was disjointed due to a lack of data-synthesis [11]. Following the production of our settlement dataset, available evidence in Lycia-Pamphylia meets a sufficient standard to test hypotheses linking climatic and socio-cultural change. Abundant palaeo-environmental datasets (15 pollen records, from 9 sites) located at varied altitudes (Figure 1c), detail past ecological conditions and the intensity of human agricultural activities [12][13][14]. Pollen in these records detail a period of human-induced landcover change known as the Beyşehir Occupation Phase (BOP), characterised by reduced presence of forest taxa and increased presence of cultivated trees [15]. For analysis in this paper, we utilise the presence of cultivated trees, represented by OJCV (Olea (Olive), Juglans (Walnut), Castanea (Chestnut) and Vitis (Grapevine)) pollen, calculated as an average of standardised percentages for archaeological periods and overlapping 200-year time windows, as a proxy for anthropogenic influence/ intensity of agricultural activities [14,16].
The potential agricultural productivity of land is heavily determined by location (including elevation) and climatic factors. In SW Turkey, effective moisture (soil moisture available to plants) is the primary climatic constraint to plant growth and, therefore, agricultural productivity [17,18]. The recent publication of a highly-resolved speleothem (stalagmite) proxy record from Kocain Cave, ~38km north of Antalya enables detailed reconstruction of regional effective moisture and precipitation amount for >3,000 years [19]. Measured ratios of magnesium with calcium (Mg/Ca) record changes in effective moisture at a very high resolution (>1 sample per year). Variations in oxygen isotope ratios (δ 18 O) provide information about past precipitation at decadal timescales (average of 9 years between samples). Two other palaeoclimate records are in our study region and cover the period under discussion. The lower resolution Lake Gölhisar δ 18 O record [20], located within the Lycian Taurus mountains at 930m asl, reflects lake-water balance, a variable akin to effective moisture, on a sub-centennial timescale (average of 71 years between samples for 1,000 BCE -1,050 CE). The multi-proxy Lake Salda record [21], located in Burdur Province at 1180m asl, extends back to ~560 CE and reflects decadal-scale changes (average of 12 years between samples for 560-1050 CE) in lake-water balance. These records detail high climatic variability during the Late Holocene, with numerous dry and wet phases identified.
Our record of settlement change is compared diachronically to these high-quality palaeo-climatic and -environmental datasets to examine the influence of climate change on settlement patterns. Based on this comparison, we argue that in our study region climate change does impact agricultural productivity, which can lead to changes in settlement density and locations. However, the relative impact is highly variable, and socio-political factors are often more important.

Study area geography
Our study region, covered by the TIB 8, pertains to the ancient regions of Lycia and Pamphylia, as well as parts of southern Pisidia, which are contained within 28°30'-32°30'E and 36°00'-38°00'N ( Figure 1b). The Western Taurus mountains form an orographic barrier to southerly and south-westerly airflows, separating the coastal and interior plateau regions into zones with distinct microclimates, ecological conditions, and high numbers of endemic species [22][23][24]. According to the Köppen-Geiger climate classification system, coastal regions are categorised as hot-summer Mediterranean (Csa) climates, with high levels of precipitation that exhibits a clear winter peak; inland regions are characterised by cold semiarid (Bsk) and Mediterranean-influenced hot/warm-summer humid continental (Dsa/b) climates [25][26][27]. Colder conditions, with reduced precipitation (~33% less) characterise the regions further inland and at higher elevations [28,29]. Fertile river valleys (e.g., the Dalaman and Köprüçay) that cut through the mountains are ideal for both rain-fed and irrigated agriculture. These run from the elevated Anatolian plateau, which is dotted with lacustrine basins and upland sheep and goat pastures called yaylas, down to indented coastlines that provide convenient natural harbours for maritime trade [30][31][32][33].

Methods
We tabulated entries in Lycia-Pamphylia from the TIB 8 to create a record of settlement change between the Bronze Age and Middle Byzantine period. The TIB is a longterm project organised by the Austrian Academy of Sciences since 1966, which has coordinated historical and modern toponyms for provinces of the Roman-Byzantine Empire with an extensive compilation of primary historical sources for all periods and relevant languages, ancient inscriptions, traveller accounts from the 19 th and 20 th centuries, and published data from extensive archaeological surveys and excavations [10]. All toponyms in the TIB 8 that could be accurately located, with archaeological or primary source evidence that could be attributed to at least one of six periods (Table 1)  The type and nature of evidence from each site was also noted according to 5 categories, in order of spatial and chronological certainty (Tables 1 and 2):  3. Material culture -mainly ceramics, also tombs and graves, coins and inscriptions located within settlements.
4. Textual reference -settlements referenced by ancient primary sources, whether in literature, or by inscriptions and mint marks of coins found outside the named settlement (e.g., the tribute lists of the Delian League).
5. Spolia -older construction materials that have been reused in ancient, medieval, or modern settlements. In large quantities from ancient and medieval contexts these portend earlier settlement at a site; settlements with limited quantities of spolia in early modern contexts that may have been transported for some distance have not been included.
Our study ends at the beginning of the Turkish conquests in the 11 th century CE, when the region became politically fragmented and the nature of both archaeological and textual evidence changed radically [9,35]. Measures of spatial and chronological resolution were assigned to each settlement, based on confidence in its location and archaeological history, for the best represented period (Table 1).

Data Critique
Significant interpretative challenges are presented when producing a settlement dataset from historical toponyms. These are analogous to those well-understood for archaeological survey data ( [36][37][38][39]; references below). Our dataset will reflect part of the original distribution of settlements, but understanding biases produced by chronological challenges and varied preservation is important to determine the accuracy of the pattern.
There are four main issues present: Firstly, the six periods utilised in this study vary in length from 250 to 1850 years (Table 1), which will lead to overemphasis of settlement numbers during longer periods.
Time-adjusted settlement numbers can also help to compensate for this bias, these are calculated (following the methodology of [37,40]) as follows: The shortest period length in our study is the Early Byzantine Period (250 years). In our discussion, we focus on periods with relatively short and similar durations.
Secondly, categorising settlements into periods by relative dating (periodisation/ "time-averaging") brings inherent bias. This makes settlements appear to exist for the entire period (the "synchronistic paradigm"; [41]). Thus, they are only given a terminus ante and post quem at the start and end of the archaeological period. For many settlements, particularly rural, it is impossible to tell whether they were occupied throughout a particular period, for a short duration, or abandoned and reoccupied [42]. Settlements can therefore appear contemporaneous though they were not (the "contemporaneity problem"; [43,44]).
The precise definition of chronological boundaries also obscures the uncertainty associated with archaeological chronologies, which rarely correspond perfectly to one-another. For instance, the Lycian-type tombs and sarcophagi that dot the landscape remain little changed between the Late Iron Age into the Early Roman period. Different strategies and resolutions for periodisation are utilised in different academic disciplines, such as by ceramicists when compared to historians.
Thirdly, destruction of evidence in later periods and time-dependent degradation will lead to an overemphasis of settlement numbers in more recent periods and alter the settlement pattern via a "preservation bias" [45]. Evidence in a particular period determines its archaeological visibility. Standing architectural remains, which constitute the bulk of archaeological evidence in our study region since the Iron Age, have an exceptional degree of preservation in Lycia-Pamphylia due to the region's relative inaccessibility and low population density. Preservation has contributed to a long history of archaeological exploration (e.g., [46]) via extensive survey and architectural description, at the expense of excavated ceramics whose publication is more limited. Ceramics are generally robust, but different raw materials and production processes determine the level of survival, and visibility, that can change the number of sherds surviving from each period: red-slip wares from the Late Hellenistic to Late Roman periods are better represented in publication, for instance [47]. In addition to the archaeological taphonomy of settlements, biases impacting the survival of ancient site toponyms may influence our record. Whilst we include some settlements with archaeological remains that can only be identified by a modern Turkish toponym, ancient toponym survival is comparatively strong in our study region, caused by the continued presence of Greek communities until population exchanges after 1923 [48].
However, the literary and historical record does yield additional ancient toponyms that cannot be securely located on the landscape, and there are likely many smaller settlements whose toponyms did not survive, left no evidence, or were subsequently destroyed.
Finally, indications of settlement or population size, whose estimates are typically dependent on measurable area within city walls or counts of housing units [49], are beyond the scope of this paper. A related problem is the nature of the historical polis, commonly translated as "city". The polis was a rank of settlement since ~600 BCE that signalled the presence of municipal government and elite investment in monumental architecture [50].
However, such settlements did not necessarily have high-density populations and most Lycian-Pamphylian cities lack substantial domestic architecture and never reached the size, density, or population, of Ephesos, Antioch, or even Tarsus [51,52]. In the Early Byzantine period the rank of polis was extended to more settlements, even as agrarian and artisanalindustrial activities were introduced within city walls [53](see Discussion). In the Middle Byzantine period, many poleis retained their status even in cases where the archaeological evidence suggests they were small villages (e.g., Pinara or Pednelissos; see Discussion). The extent to which Lycian-Pamphylian poleis or "cities" may be classified as low-or high-density urban environments is therefore irresolvable in many cases [54]. In our metadata, increasing settlement density across the study region could therefore represent expansion or fragmentation, with associated population increases or decreases. Settlement types, so far as they can be reconstructed, are included in our full data (Table S1).

Results
Within our study area, 381 out of the total 1038 toponym entries in TIB 8 could be located and identified as a settlement, with sufficient survival or publication to enable identification of historical presence between the Bronze Age and the Middle Byzantine period ( Table 2). The remaining 658 entries were either duplicates, dated to later periods only, infrastructure not associated with settlement (e.g., bridges), natural phenomena (e.g., rivers, mountains), regional toponyms, or their location was unknown. Toponyms associated with settlements are varied, including cities, farmsteads, peri-urban harbours and temples, hilltop fortifications, island villages and caves. Settlement function, size, and status changed over time. Of 381 settlements, only 8 were occupied in all six periods and 283 or ¾ of the total contained evidence for 1-3 periods ( Figure S2). Elevation of settlements varied overall, ranging from 0 to 1835m asl, and by period (Figures 2 and 5). However, lower elevation settlements dominate, with 29.4% at elevations <200m asl and 70% at elevations <1,000m asl. Most settlements (291) could be located to <1km and only a very small portion (14) could not be located to <3km (Table 2). Chronological resolution of settlements was weaker, with only 56 excavated or systematically surveyed and published. A total of 226 settlements were extensively surveyed but with reliance on rather broad and primarily architectural indications for chronology. The remaining 99 have weak chronological resolutions, being only summarily visited by travellers or scholars since 1800 CE, or dated by re-used building materials, easily recognisable within later buildings (e.g., Classical architectural sculpture or inscriptions recycled in Late Roman fortifications). The character of settlement evidence also varied by period (Figures 2c and 3). Table 3: Settlement metadata by period. "New" settlements are those with evidence in the period, but no evidence in the preceding period; "Continued" settlements are those with evidence in the period and preceding period; "Abandoned" settlements are those with no evidence in the period, but evidence in the preceding period; time-adjusted settlement numbers are calculated following the methodology of Contreras et al., (2018) and Barton et al., (1994    Interpreting changes in the number and locations of settlements for each period presents significant challenges, associated with chronology, interpretive uncertainty, and preservation bias (see Data Critique). However, some patterns are still observable and broadly consistent with the regional history, archaeological evidence, and palaeoenvironmental data. The clearest of these trends is a steady increase and peak of settlement numbers in the Roman and Early Byzantine periods, followed by a significant reduction of Middle Byzantine evidence (Figures 2a and 3). These changes are consistent with data from across the Eastern Mediterranean [1,55,56] and are frequently hypothesised to result in part from changing climatic and environmental conditions. We discuss these hypotheses below, utilising a regional case-study approach that includes comparison of our dataset with pre-existing evidence.

History of Climate and Society in the Eastern Mediterranean
Studying associations between climatic and socio-cultural change, now termed the 'history of climate and society' (HCS; [57]) in the Eastern Mediterranean has been extensive, due to the region's historical significance, and a focus of many popular-science books [58][59][60]. Generally, such studies produce climate reconstructions which can be, linked to largescale climatic periods or events (such as those displayed in Figure 6c), from a combination of palaeoclimate proxy records, model simulations, and historical records. Assembled climate evidence is then compared to historical and archaeological evidence for social, economic, and cultural change, to assess human-climate-environment relationships. These studies intend to provide insight into past societal resilience and fragility, to prepare for potential impacts of future climate change [8,61]. However, reviews of HCS studies [57,[62][63][64][65] have identified significant and recurring issues, namely (1) correlation-based conclusions that lack convincing causal explanations, (2) a bias towards periods of "crisis" which mischaracterises human-environment interactions, (3) a focus on large regions without high-quality comparative datasets, leading to calls for "micro-regional" case-studies (stressed originally in [6]), and (4) the interdisciplinary challenge of comparing archaeological, palaeoenvironmental, and -climatic data of varied resolutions. These challenges are confronted in our presentation of regional data for climate and society in Lycia-Pamphylia. There are several key criticisms of these types of hypotheses, linked to the above broader criticisms of HCS studies. Most apparent is the generalised and large-scale nature of such hypotheses. Thus, care must be taken when discussing generalised patterns for broad regions or periods, as both climatic and socio-economic conditions have the potential for high variability on both spatial and temporal scales, especially in the Eastern Mediterranean [6][7][8]11,19]. Regional analyses are therefore required where the main climatic constraints on agricultural productivity are identified. For most regions in the Eastern Mediterranean, the basic assumption that higher temperatures and water availability will facilitate higher agricultural productivity is too simplistic [3,17]. A regional scale analysis of Lycia-Pamphylia is enabled by our new dataset of settlement character and location, and the existing high quality palaeo-environmental and -climatic records. Chronological and preservation biases in settlement datasets are limiting factors for this analysis (see Data Critique). However, the consistency of patterns across varied data-types, particularly for the Roman to Middle Byzantine periods, suggests they result from regional changes in settlement density and distribution. Comparing datasets of different temporal resolutions, such as highly-resolved palaeoclimate records and period-averaged settlement data, presents significant challenges.
Averaging of high-resolution palaeoclimate data for archaeological periods or centuries is one methodology frequently utilised in the Eastern Mediterranean (e.g., [2,56,74]), here providing interesting results (Figures 6a and 6b). A visual relationship between δ 18 O and settlement evidence is apparent (Figure 6b). However, century-long averages are misleading, and conceal the high variability of climatic conditions within each period (Figure 6c).
Additionally, agricultural productivity is more reliant on effective moisture, which for the higher resolution Kocain Mg/Ca record [19] shows a weaker relationship (note the Roman Period in Figure 6a). In the sections below, we consider the full picture of climatic variability during the periods under discussion and assess the extent of their impact on regional settlement location and character, in addition to the contribution of other factors.

A Roman Climatic Optimum?
Roman settlements in our dataset were largely continuous with the preceding    [85,86]. More than a century of heavy investment followed, which was financed by both the state and by local elites choosing to incorporate their lands into the Roman imperial system [87,88].
Monumental agorai, theatres, baths, aqueducts, and temples, were rapidly constructed in both coastal and upland Roman settlements (Figure 4b; [85,89]). Interconnectivity increased with infrastructural investment, and agricultural products critical for supply of Roman armies on the Danube and Syrian-Mesopotamian frontiers were more readily exported [90]. Roads were systematised, as evidenced by milestone inscriptions and the important Stadiasmus Patarensis inscription of regional road networks [91]. Lycian harbours became important nodes in regional grain markets and saw significant infrastructure upgrades. For example, granaries were built at Andriake and Patara, with a lighthouse at the latter [92]. Tax collection from cities was standardised across Roman territory and the state now profited from the rich resources of Lycia-Pamphylia, including traditional agricultural produce but also sponges, goat hair for ropes, wild animals for the circus, fish processed as garum, and, most importantly, timber [85,86]. Agricultural efficiency for the Mediterranean triad (grapes, grains and olives) was enhanced with Roman innovation of the screw press for grapes and olives and the rotary mill for grain [93,94]. Roman hegemony also brought newfound security from unrest and a regional threat of banditry and looters [86], and might be reflected by a reduction in both urban fortifications and tower-farmsteads, as noted earlier [95,96]. All the above factors increased the importance of Lycia-Pamphylia for trade and enabled intensification of settlement and agriculture in the hinterlands [92,97]. These developments occurred despite prevailing climatic conditions that likely made agriculture more challenging when compared to the preceding and succeeding periods. The dense settlement detected in the Roman period continues into the Early Byzantine period, however a shift in the character and location of settlement is observed.

Late Antique prosperity and adaptation?
Settlement numbers peaked in the Roman period 50 BCE-350 CE, with the majority continuing into the Early Byzantine period 350-600 CE (189/276 Roman settlements: 68%).
Overall settlement numbers remained high, with a slight decline in absolute numbers, with 255 of 381 settlements total (67%) dated to the Early Byzantine period. When bias from period length is counteracted by a time-adjustment (see Data Critique), the Early Byzantine period experiences the settlement evidence peak (Figure 2b). Important, however, is the shifting character and location of settlement between these two periods. There is a loss of settlement density in interior Lycia (Figures 3 and S3) caused by the abandonment of Roman Period highland rural settlements, which contributed to the highest mean elevation of abandonments for any period (814m asl). Dense settlement on the coast continues however, with 87 settlements <200m asl, including older Hellenistic and Roman cities ( Figure S3). New rural settlements also appear in the hinterlands of these cities, for instance around Fethiye, Olüdeniz, and Myra; the lowest mean elevation of new settlements for any period (514m asl) lowers the overall mean elevation (575m asl; Figures 3 and 4).
These findings are largely coherent with regional understanding. Though Martin Harrison [98] previously suggested that coastal cities in Lycia declined from the 5 th century CE, with population and important settlements migrating inland to the mountainous regions, the inverse has otherwise been suggested -and is supported by our dataset -with increased settlement density in coastal regions and a possible decline in the interior regions [11,35,39,99,100]. The pollen data provides further support for this trend, with an Early Byzantine period decline in OJCV values at the high elevation Sögüt and Bereket Basin sites ( Figure 7), coincident with the end of the BOP ended at these sites [15]. A decline in OJCV values is also observed in the other records from around Sagalassos (Ağlasun and Gravgaz Marsh), coincident with a reduction in settlement numbers in the hinterland survey (Figure 7; [78]). Similar to the Roman period, long-distance maritime transport of agricultural produce was important, with the state subsidising supply of food staples both to Constantinople and to Byzantine armies campaigning against Sassanid Persia [101,102]. This may have promoted expansion of settlements near to the coastlines and made inaccessible mountainside settlements comparatively less efficient [11,69]. Because lower coastal regions have enhanced precipitation compared to the higher elevation interior and have an extended growing season, they are more productive and allow for greater crop diversity [70]. The idea of a period of "prosperity" in the 4 th -6 th centuries CE is therefore more complicated, at least in Lycia-Pamphylia [11,35].
Adam Izdebski et al. [1] examined Early Byzantine "prosperity" in relation to climatic conditions, concluding that enhanced precipitation contributed to the expansion of rural settlement and agriculture into environmentally marginal terrain. However, at that time the only available high-resolution palaeoclimate records in Anatolia were those from Nar Gölü [103][104][105] and Sofular Cave [106], located in the Central Anatolian Plateau and Black Sea coastal regions, respectively. These records, and associated archaeological and historical data, suggest enhanced aridity 350-470 CE, followed by wetter conditions [1]. However, the climate of Lycia-Pamphylia is now better understood due to the local Kocain Cave record [19], which stresses spatial heterogeneity of climate in Anatolia. The record demonstrates that the SW region experienced the inverse pattern to that previously suggested, sharing more similarities with the Aegean [19,74]. Kocain δ 18 O and Mg/Ca ratios indicate very high precipitation and effective moisture between 330 and 400-460 CE, followed by a rapid shift to drier conditions that persisted until ~830 CE ( Figure 6). This is important as highresolution variability of climatic conditions in SW Anatolia were previously unknown for most of this period. The Lake Salda record, for instance, starts at ~560 CE, and there are no historical references to climatic conditions from the region [20,21,107].
Reduced effective moisture from the mid-5 th century CE may also be reflected in regional archaeological evidence for urban water infrastructure adaptations. Construction and refurbishment of large vaulted reservoirs for water storage escalated from the mid-5 th century CE, with large-scale projects at seven of the regions major cities, including the wellexcavated sites of Sagalassos, Patara, Rhodiapolis, Side, and Xanthos [108][109][110][111]. At Sagalassos, a reduction in the supply output of the older Roman aqueducts is visible in changes made to the city's fountains during the 6 th century, with outlets cut at lower basin levels in the Upper Agora, alongside construction of new metal and textile workshops. New public fountains were still constructed in Sagalassos; geochemical evidence from calcites in feeder channels indicates supply via rain-capture and snow-melt [108], contrary to traditional Roman patterns of urban water supply via spring-fed aqueducts [112,113]. New settlements entirely reliant on rainwater capture also appear in the Early Byzantine period, for instance at Lyrboton Kome [9] and Gemiler Adasi [114]. These urban water infrastructure adaptations coincide with the demonumentalisation and ruralisation of cities, the appearance of church architecture, and renewal of fortifications described below. These economising adaptations are traditionally associated in scholarship with "decline" but lately considered to be indicative of "adaptive reuse" [101], here possibly linked to drier climatic conditions revealed by the Kocain Cave multi-proxy record.
Early Byzantine settlement is most clearly evidenced by church architecture, which appears almost exclusively after the mid-5 th century CE [9].  115]. Churches are also found in close proximity to agricultural developments in the countryside such as terracing (as at Asarcik, but unfortunately not dated; e.g., as in [116]) and in cities near artisanal installations (at Patara and Sagalassos), or large scale water storage (at Xanthos and Gemiler Adasi). At Xanthos, for instance, recent excavations in the western agora have revealed two churches, one at the agora's center and one built into its western portico, surrounded by workshops and water installations that facilitated artisanal activity, all dated to the fifth and sixth centuries ( Figure   4e; [117]). Whilst new churches are not necessarily indications of communal wealth, they did require significant investment [69,118]. This was especially true in Lycia where churches featured high-quality stone carving, even within village settings (e.g., north of Demre around Asarcık, Figure 4c; [119]). Lycian churches have long been a focus of scholarly attention (e.g., [46]), which, combined with their robustness, increases the archaeological visibility of rural settlements. These factors are perhaps reflected in the increase of rural settlements in our data between the Roman (43%: 119) and Early Byzantine (51%: 130) periods.
From the mid-5 th century CE, older Roman cities saw growing industrialization throughout our region but began to lose their monumental aspect, alongside adaptation or reconstruction of older Roman public buildings (including theaters, baths, and agorai) for artisanal and industrial activities. For instance at Side, glass workshops appeared in the theater and around an abandoned temple in the agora after the 5 th century [120,121]. At Limyra, baths near the theater were abandoned in the later fifth century CE and became home to workshops for textiles, metal and/or glass, and bone-carving [122]. At Andriake, a workshop for the extraction of precious murex dye was built in the 6 th century using spolia from an older church: remaining were massive piles of murex shells and more than 22,000 amphorae fragments of the sixth and seventh centuries thought to be related to murex production and transport there [123,124].
Whilst reduced effective moisture appears in southwest Anatolia after ~450 CE, climatic shifts will not be homogenous across the Eastern Mediterranean. A complex web of interconnected natural and human factors for societal change in the Byzantine periods is suggested elsewhere to have its origin in the mid-6 th century CE. These include cooling and drying associated with volcanic-induced reductions in solar irradiation, earthquakes, and epidemics, and insecurity resulting from conflicts between the Byzantine and Sasanian Empires, the Umayyad Caliphate, and nomadic groups. These are discussed in the below section.

Middle Byzantine Abandonment and Renucleation?
The transition between our Early Byzantine-Middle Byzantine periods, from c. 550 to 650 or 700 CE, shows a significant shift in the intensity and character of settlement.
Settlement density was reduced in the Middle Byzantine period, with a total of 135 settlements. Of the settlements with Early Byzantine period evidence, 134/255 (52%) had been abandoned and only 17 new settlements are evidenced. An even more pronounced reduction is settlement density is suggested when the length of the longer period is considered, with time-adjustments (see Data Critique; Figure 2b).
Additionally, settlements were no longer occupied at the scales of the preceding Roman and Early Byzantine periods: In larger urban settlements elsewhere, a citte ad isole pattern is frequently observed, whereby small clusters of agro-industrial activity or "islands" are visible within the skeleton of older Roman and Early Byzantine cities, which were otherwise uninhabited. For example, Myra contained three separate fortified enclosures: one at the acropolis [125], one at the Church of St Nicholas, which was rebuilt as a domed basilica in the 8 th century CE [126], and one at the city's harbour, Andriake [35]. Antalya, which became a centre for the Byzantine navy and administration alongside significant investment in new architecture and fortifications may be one exception, though 20 th century development has prevented any archaeological conclusions [9]. Furthermore, over half (72/135)  renucleation. Major church construction (e.g., at Antalya, Myra, Patara) and resettlement of disused urban acropolises (e.g., at Perge, Tlos, Xanthos) was accompanied by increased administrative importance [127]. Byzantine lead seals, which were used to secure documents and indicate information about the author [128], demonstrate the importance of Antalya, Myra, Perge, and Tlos, as centres of Byzantine naval and fiscal administration in the Kibyrrhaeot theme [9,129] (Table S3).
Other regional surveys, relying primarily on ceramic evidence, show divergent patterns (Figure 7). In the Sagalassos hinterland survey, settlement numbers had already declined for the period starting at ~450 CE, whereas in the Dereköy Highland sherd counts remained high in their period starting 700 CE [78,130,131]. In the Balboura survey, sherd count increases in the 7 th century CE, after re-dating of Cypriot Red Slip Ware (CRSW) by Armstrong [132] -a local/regional production that satisfies basic household needs [133]. In both surveys, the majority of Middle Byzantine sherds are local [134][135][136][137]. This pattern, which suggests a reduction in inter-regional exchange, is observed across the region, at settlements such as Sagalassos, Limyra and Xanthos [77,101,138]. This reduction in interregional exchange was accompanied by a reconfiguration in some contexts, away from Constantinople and towards the southeast: 7 th -9 th century CE deposits from Sagalassos contained LR7 amphora with fish remains from Egypt, and deposits from Limyra contained wares from Cyprus, Egypt, and the Levant [139].
The transition from the Early to Middle Byzantine periods also marks a major shift in the agricultural history of our study region and the Eastern Mediterranean more broadly.
Intensive crop cultivation slowed considerably, pastoralism grew in importance, and rewilding of the landscape occurred with pine forest recolonisation [79,140,141]. At the pollen sites where the BOP had not already ended (Gölhisar, Ağlasun, Gravgaz), it did in the 7 th -8 th CE (summarised in [15]). This is reflected in the OJCV values (Figures 7 and S4 [19,146]). Records from elsewhere in Anatolia, in Lake Nar and Sofular Cave, show either wetter conditions or no indication of a climatic impact from the 536-550 CE downturn [103][104][105][106], further stressing regional and local climatic variability.
An extended dry period is suggested for Lycia-Pamphylia (~460-830 CE) that would have lowered potential agricultural productivity, potentially disenabling arboriculture at higher elevations, and may have contributed to socio-economic and settlement decline.
However, it is important to consider that there were earlier instances of dry climatic conditions where the local population appears to be relatively unafflicted, or even to have prospered. For example, during exceptionally dry conditions in the middle of the Iron Age (800 and 700 BCE), Greek colonisation started in our region and, during the RCO agriculture thrived despite relatively low effective moisture. Additionally, the shift to drier conditions occurred at least a century earlier than the reduction in settlement numbers and investment, with a shift away from agriculture and towards pastoralism, which can be broadly dated to somewhere between 550 and 650 CE. This suggests that either the duration of the climatic change, or its combination with other factors was more important. These are primarily (1) pathogenic, (2) seismic, and (3) defensive.
(1) The appearance of the Plague of Justinian after 541 CE and lasting into the 8 th century CE, an early epidemic of the bubonic plague caused by the bacterium Yersinia pestis, was traditionally understood as a mass mortality event, especially during the 540s CE [60,147]. Its presence in Lycia-Pamphylia is securely evidenced, with a detailed and contemporary account of widespread death at Myra, probably in 542 CE, that interrupted agricultural commerce from the Lycian interior to the port-city [107,148], and aDNA of Yersinia pestis identified from human remains at Sagalassos [149]. However, the demographic impact of the pandemic has recently been questioned [150][151][152]. The historical account of Myra also indicates recovery of the rural landscape thereafter [107,147,148] and, with the exception of the single victim at Sagalassos, aDNA is lacking for now [149]. Late Antique plague may have been a greater stimulus for shifts in religio-cultural beliefs and traditions than demographic or economic problems [153][154][155]. However, regional evidence indicates plague's presence, and it cannot be excluded as a factor in the widespread settlement abandonment, and possible demographic contraction, that is clearly visible in the archaeology of Lycia-Pamphylia between the mid-6 th and 7 th centuries CE.
(2) Another major factor in 6 th century changes elsewhere, and with evidence for in our study region, are earthquakes [73,156]. The Aegean tectonic plate, a subduction zone, nearly parallel to and offshore from the south Anatolian coast [157], causes frequent earthquakes in Lycia-Pamphylia [158]. An early 6 th century (possibly 500 or 518 CE) earthquake occurred north of Antalya [159,160], collapsing numerous light buildings and the monumental gates at Sagalassos [161,162], with rebuilding activities widely visible in the city's archaeology [163]. In 528/9 CE, an earthquake centred on Fethiye-Meis [164] caused extensive damage across Lycia, particularly at Myra [165], with support given from imperial funds for reconstruction, according to typical protocols [156]. Communities suffering from earthquakes after the 6 th century did not receive help or repair, however. Another earthquake around 600 CE "virtually wiped out Sagalassos as an urban settlement" [163] and further earthquakes in the seventh and eighth centuries have been observed in damaged and unrepaired structures at Side and around Myra [9].
(3) Regional insecurity also increased from the 7 th century. Towards the end of the An interesting suggestion, beyond the scope of this paper, is that the complex web of interconnected factors (including climatic deterioration), which impacted varied regions across the northern hemisphere, may have "pushed" or "enabled" invasions by the Rashidun/Umayyad Caliphates [73], and nomadic groups [71].
Overall, evidence from Lycia-Pamphylia indicates settlement abandonment and contraction suggestive of demographic contraction, a shift from BOP agriculture to pastoralism, and the presence of dry climatic conditions, plague, earthquakes, and insecurity -all present at the transition between our Early and Middle Byzantine periods ("end of Late Antiquity") after the 6 th century CE. However, clear causal attribution between archaeologically-visible developments and the aforementioned factors remain difficult to determine throughout Anatolia [168]. Evidence is overall stronger for the natural hazards, when compared to the evidence for societal response to them. Better chronological precision for archaeological change and site-specific studies of proxies for societal response (e.g., urban trash mounds [4]) are required to disentangle the causes of this change. Additionally, as with climate, there are earlier instances of plagues, earthquakes, and conflicts, where the population of Lycia-Pamphylia appear to have been unafflicted (see [156,169] for earthquakes). This emphasises these factors were contributory, rather than ultimate, and that it is ultimately socio-political factors that determine regional resilience and ability to adapt.

Conclusions
The regional record of historical settlements provided by the TIB 8, combined with regional climatic and environmental proxies, provides a clear picture of settlement change for a region with previously disjointed evidence. Settlement numbers peak between the first century BCE and the sixth century CE in the Roman and Early Byzantine periods, alongside evolutions in the character and locations of settlement that begin ~460 CE, followed by a clear decline in absolute numbers that continues into the Middle Byzantine period. These shifts occur prior to the LALIA, increased seismic activity and the beginning of the Justinianic Plague, though they appear to have been intensified by the latter.
We find that, during the "Pax Romana" (1 st and 2 nd centuries CE), increasing agricultural productivity, settlement numbers, and population, with economic investment, does occur. However, linking these developments to warmer and wetter climatic conditions Examining human-climate-environment interactions has been demonstrated as requiring strong archaeological and historical evidence, as well as high-quality palaeoenvironmental and -climatic datasets. Further similar work can be done utilising earlier periods in this archaeological dataset. For example, interesting settlement, environmental, and climatic, changes are identified in the Iron Age and Hellenistic period. Additionally, similar archaeological datasets can be produced in existing and upcoming TIB regions [170], many of which contain highly-resolved speleothem and lake palaeoclimate records suitable for similar analysis: Cappadocia (Nar Lake [103]), Nicopolis and Cephalonia (Lake Trichonida [171]), Thrace (Uzuntarla Cave [172]), Bithynia (Sofular Cave [106,173]) and the Northern Aegean (Skala Marion Cave [174]). Furthermore, the Kocain Cave Mg/Ca record (and other high-resolution effective moisture records) may enable agroecosystem modelling of agricultural productivity for these regions (as in [37,175]).